Darpa, the Pentagon’s advanced-research unit–AKA, the place where they develop Men In Black technology–is working on a flapping robo-sentinel. Aerovironment, the company that’s been developing the gadget, just revealed video of the progress they’ve made, working off of a $2.1 million Darpa grant:

This is the first-ever hovering air vehicle to use flapping wings while carrying its own power source. The hope is that the hummingbird will be useful for indoor and outdoor surveillance, as well as dropping off listening devices and other super-spy cargo.

Why go through the trouble? Why not just build a tiny helicopter? Supposedly, craft like these can fly with far greater airborne efficiency–no wonder birds have wings rather than rotary blades–which would eventually lead to more flight with every refuel. The next prototype is expected to be even smaller, weighing just 10 grams; faster, with a top speed of 22 mph; quieter, and more wind resistant.